Positron emission tomography (PET) and single photon emission computed tomography (SPECT) procedures typically rely on positron or gamma ray emitting radionuclides with short half-lives. For example, PET procedures frequently rely on 18F-deoxyglucose (FDG) while many SPECT procedures rely on conjugated 99mTc compounds.
18F has a half-life of less than 2 hours, while 99mTc has a half-life of about 6 hours. The volume of a solution carrying a tracer must be carefully calculated for administration of a specific radiation dose to a patient. Because of the (relatively) short half-lives of these types of radionuclides, a delay in patient administration may require a dynamic adjustment of the volume of the radionuclide solution. Even a delay of 15 minutes (for example, because of traffic delaying a patient's arrival at the test site) for the injection may significantly change the amount of solution volume necessary to supply a correct radionuclide dose. As such, the amount of radionuclide that is distributed to a treatment location typically exceeds the required dose. As a result, a technician is required to measure the activity level of the radionuclide and discard the excess radionuclide. This process is subject to errors in measurement by the technician and exposure of the technician to radiation from the disposal of the excess radionuclide. It is therefore useful to develop an injection syringe capable of on-the-fly adjustment of dose volume of a solution of a radionuclide material that reduces the risk of exposure to harmful radiation.